40MPa Steel Lightweight Seamless High-Pressure Air Cylinder
On the basis of studying the development status of existing steel seamless high-pressure gas cylinders at home and abroad, this paper carefully analyzes the key technical links in the manufacture of related gas cylinders, and formulates a technical plan for the development of 40MPa light seamless high-pressure gas cylinders for the key technical links . Through the structural design of the gas cylinder, as well as the stress analysis and fatigue analysis of the gas cylinder using the finite element method, the technical feasibility and safety of the gas cylinder product are further demonstrated. According to the development technical plan, the trial production of a short-sized prototype was carried out, and the tests of non-destructive flaw detection, air tightness, water pressure and blasting were carried out on the prototype.
It is completely feasible to trial-manufacture the 40MPa steel lightweight seamless high-pressure air bottle prototype using the newly developed XXX material .
Current status of high pressure vessels at home and abroad
Summary of Domestic and Foreign Standards
The commonly used standards, steel grades and uses of high-pressure vessels and seamless steel pipes in China, the United States, Japan, Germany, Russia and other countries are shown in Table 1 . Table 1 List of commonly used standards, steel grades and uses of high-pressure vessels and seamless steel pipes in China, the United States, Japan, Germany, Russia and other countries
Country |
Standard for high pressure vessels and steel pipes |
Common steel grade |
use |
|
China |
GB5099, GB17258, GB18248 , |
20 (A) , 37Mn , 34Mn2VA , 35CrMo |
Used in the manufacture of general high-pressure gas cylinders or special gas cylinders, accumulators (of which 20 (A) can be used to manufacture medium-pressure accumulators), 32CrNi2MoVA and |
|
U.S. |
ASME SA-372 , SA-723 , |
AM type steel grades of various levels (a total of 3 types |
Used to manufacture various high-pressure vessels with a pressure range of 10. 3-6 & 9MPa , among which Crl , Cr2 and Cr3 in SA-723 are used to manufacture ultra-high pressure vessels |
|
Japan |
JISG3429 , JISG3459 , |
STH11 , STH12, STH21, STH21 , |
pipes for manufacturing |
|
Country |
Standard for high pressure vessels and steel pipes |
Commonly used steel grades . |
use |
|
|
|
c |
Some stainless steel pipes or forgings are used to manufacture high-pressure gas cylinders in the above two standards; A , B , and C forgings are often used to manufacture ultra-high pressure vessels |
|
Germany |
DIN17200.DIN2448 , DIN4664 |
37Mn2 , 46Mn7 > 25CrMo4 , |
Used in the manufacture of high-pressure gas cylinders and various high-pressure containers, among which 30CrNiMo8 is often used in the manufacture of ultra-high pressure containers |
|
Russia |
roc t 4543 , v oct 8731 , |
30XMA , 20XH4①A , 37XH3M①A , _ _ _ _ |
For the manufacture of high-pressure gas cylinders, special |
With the development of high-pressure vessels and their types of tubes, the standards that are widely used in the world and are constantly being revised and improved are not only those mentioned in Table 1 , but also IS0/CD11437, IS011120 " 150-3000L Seamless Steel Gas Cylinder Design , Manufacturing and Testing Standards" ( 1st edition, 1999 ), etc. With the continuous increase of domestic demand and the continuous introduction of foreign products, the domestic high-pressure vessel and its pipe standards are also constantly revised and improved, because there are differences in parameter definition, design calculation, manufacturing, inspection and many other aspects among the standards. , needs to be understood and executed correctly in order to design and manufacture products more suitable for national conditions. At the same time, combined with the further improvement of the pipe-making process and the acceleration of the modernization process, China is fully capable of producing seamless steel pipes for high-quality high-pressure vessels with a larger size range, higher precision, more steel types and specifications, and different quality requirements.
Domestic status
Material
Domestic production of seamless steel pipes for gas cylinders started in the 1960s , with 35 and 45 steels, and DZ40 steel was generally used in the 1970s ; by the 1980s , steel pipes for steel gas cylinders had been mass-produced. From the mid- 1980s to the mid- 1990s , with the establishment and revision of national gas cylinder standards and the expansion of the scope of use of gas cylinders, in order to improve low-temperature impact toughness and integrate with international standards as soon as possible, China vigorously developed low volume-to-weight ratio, high working pressure, and safety. Gas cylinders that are durable, free from stress corrosion or hydrogen embrittlement, so gas cylinders made of Cr-Mo materials are rapidly developed, but the maximum pressure stays below 30MPa , and the gas cylinder materials suitable for higher strength pressure are still being trial-produced and tested middle.
Production Process
Domestic production of high-pressure seamless steel pipes in the 1970s and 1980s mainly relied on automatic pipe rolling and periodic pipe rolling processes to supply blanks for medium and small gas cylinders; pipes for large-caliber high-pressure gas cylinders were based on hot-rolled pipes and continued to be processed through thermal expansion. process to enlarge the outer diameter and reduce the wall thickness. In order to obtain a cylinder tube with thinner wall thickness, smoother surface, and higher accuracy of outer diameter and wall thickness, the spinning process is also required. Since the late 1980s , with the development of domestic pipe rolling technology, alloy steel pipes can be produced in terms of large pipe jacking, which has laid a solid foundation for the production of large volume and high pressure gas cylinders and containers in China. In addition, the smelting, machining, non-destructive testing, finishing equipment and technology of various steel pipe factories have been increasingly perfected and modernized, which also provides better means for the deep processing and testing of high-pressure gas cylinders and container pipes.
production development
the 1960s and 1970s, China has successively developed carbon steel general high-pressure gas cylinder tubes with ① 219 as the main specification; in the 1980s , the first generation of Luo Niu steel gas cylinders and Accumulator tubes; In the early 1990s , the steel grades, specifications, and output of general high-pressure gas cylinder tubes continued to expand; since the mid- to -late 1990s , special high-pressure gas cylinder tubes have developed rapidly and gradually occupied the domestic market . Pipes for high-pressure vessels in various fields, steel grades, and larger specifications are being continuously researched and developed.
Status abroad
Material
Early gas cylinders in foreign countries mostly used carbon steel and mammoth steel. Since the end of the middle of this century, mammoth steel and saw button steel have been basically used. Meng steel is low in cost, high in strength, and has good non-aging sensitivity. After oil quenching + tempering is used for heat treatment, it has good toughness and is suitable for manufacturing gas cylinders with a working pressure of 14 ~ 17MPa , and the operating temperature is -20°;C~60°;C Economical and practical material for C gas cylinders, especially suitable for filling permanent gases. In the 1960s , saw button steel and other alloy steel materials were developed in large quantities; in the early 1980s , 37CrNi3MoVA steel was used to manufacture small-capacity high-pressure cylinders with a working pressure of 40MPa . This steel has good low-temperature impact toughness and fatigue resistance. Mingguan steel and other alloy steel gas cylinders are generally used after quenching and tempering. This type of gas cylinder has higher strength than Menggang steel gas cylinders, better low-temperature impact energy (-50°;C, V- type), and can resist cyclic fatigue. High pressure and light weight are suitable for use in cold regions, oceans, aerospace, deep wells and other special environments; and lighter high-pressure gas cylinders with lower volume-to-weight ratios are the main development trend in recent years.
Production Process
At present, the United States, Britain, Germany, Russia, Japan, France, Italy and other countries are the main countries that produce various types of high-pressure gas cylinders and containers in the world. The main processes for producing seamless steel pipes for high-pressure gas cylinders are pipe rolling and big top Tubes, the former can produce tubes for small-volume gas cylinders with cold rolling (drawing) process, and can produce large-volume gas cylinders with thermal expansion.
production development
The high-pressure vessels produced by American CPI Company according to DOT and ASME standards generally have a storage pressure of 10.3 ~ 68.9MPa and a wide range of operating temperatures. The varieties include aerospace, chemical, construction, food, industrial control, nuclear power plants, Oil and gas development and production, fire protection, sanitation and first aid facilities, transportation and seabed exploration and other fields are mainly used to store hydrogen, natural gas, nitrogen, air, ammonia, oxygen and other gases and compressed liquids. The trailer bottles and pipes produced by Italy Dalmin have been sold to my country. South Korea has also entered the Chinese market using trailers made by Japan's trailer management system.
skills requirement
basic structure
Cylindrical cylinders are the most widely used in high-pressure gas cylinders, which are easy to arrange, have smooth curved surfaces, relatively uniform stress distribution, do not cause large additional stress, and are relatively easy to manufacture and install gas cylinder accessories. The 40MPa steel lightweight seamless high-pressure air bottle introduced in this article adopts a double-necked cylindrical structure:
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